Microbial Primary Metabolites: Biosynthesis and Perspectives

Abstract

The microbial production of primary metabolites contributes significantly to the quality of life. Fermentative production of these compounds is still an important goal of modern biotechnology. Through fermentation, microorganisms growing on inexpensive carbon and nitrogen sources produce valuable products such as amino acids, nucleotides, organic acids, and vitamins, which can be added to food to enhance its flavor, or increase its nutritive values. The contribution of microorganisms goes well beyond the food and health industries with the renewed interest in solvent fermentations. Microorganisms have the potential to provide many petroleum‐derived products as well as the ethanol necessary for liquid fuel. Additional applications of primary metabolites lie in their impact as precursors of many pharmaceutical compounds. The roles of primary metabolites and the microbes which produce them will certainly increase in importance as time goes on. Overproduction of microbial metabolites is related to developmental phases of microorganisms. Inducers, effectors, inhibitors, and various signal molecules play a role in different types of overproduction. Biosynthesis of enzymes catalyzing metabolic reactions in microbial cells is controlled by well‐known positive and negative mechanisms, for example, induction, nutritional regulation (carbon or nitrogen source regulation), and feedback regulation. In the early years of fermentation processes, development of producing strains initially depended on classical strain breeding involving repeated random mutations, each followed by screening or selection. More recently, methods of molecular genetics have been used for the overproduction of primary metabolic products. The development of modern tools of molecular biology enabled more rational approaches for strain improvement. Techniques of transcriptome, proteome, and metabolome analysis, as well as metabolic flux analysis, have recently been introduced in order to identify new and important target genes and to quantify metabolic activities necessary for further strain improvement.

Mycofabrication of common plasmonic colloids, theoretical considerations, mechanism and potential applications

“…vitamins. The primary metabolites of catabolic metabolism, citric acid, acetic acid, and ethanol, are not biosynthetic precursors but their production, which are related to energy production and substrate utilisation, are essential for growth [87].…”

Metabolic Engineering and Fermentation Process Strategies for L-Tryptophan Production by Escherichia coli

“…L-Tryptophan, an essential amino acid for human and animal activity, can serve as a supplement in the food and feed industry, as well as medicine to promote good sleep quality and mood [5,6]. The annual demand of L-tryptophan in the global market is above 50,000 tons, and the market growth rate is over 10% [7]. With the rapid growth of market demand, the development of L-tryptophan production technologies has received considerable research attention around the globe.…”